How to play an underpair?-BSS

Let’s say I have QQ on a Kxx flop, or KK on a Axx flop. Usually in these cases I make a c-bet. But I turn my underpair into a bluff. If he’s not a fish, my opponent will only call me with better hands and will lay down the hands that I beat. If I make a c-bet I will gain information, but betting for information is not good. If I play passively, I have a tough decision if my opponent bets. What is the optimal strategy against an unknown opponent(I don’t have Pokertracker and I play 6 tables, so the majority of my opponents are unknown)?

In general I would say play b/f on the flop. Getting informations is better against unknown than taking tough spots. Play check behind on th turn if you are in position and decide on the river if you can call a bet, fold to a bet, check behind or even value bet again. If the board is draw heavy you can also think about firing the turn again. Try to get a feeling for board structures and types of opponents.